MENU

RD Chapter 7 Statistics Ex 7.2 Solutions

Question - 1 : -
The. number of telephone calls received at an exchange per interval for 250 successive one-minute intervals are given in the following frequency table:
 
Compute the mean number of calls per interval.

Answer - 1 : -

Let assumed mean (A) = 4
 
Hence mean number of calls per interval = 3.54

Question - 2 : - Five coins were simultaneously tossed 1000 times, and at each toss the number of heads was observed. The number of tosses during which 0, 1, 2, 3, 4, and 5 heads were obtained are shown in the table below. Find the mean number of heads per toss

Answer - 2 : -

Let assumed means (A) = 3
 
Hence mean number of tosses per head = 2.47

Question - 3 : -
The following table gives the number of branches and number of plants in the garden of a school.
 
Calculate the average number of branches per plant.

Answer - 3 : -


∴Meannumber of branches per plant = 3.62

Question - 4 : -
The following table gives the number of children of 150 families in a village
 
Find the average number of children per family.

Answer - 4 : -

Let assumed mean (A) = 3
 
= 3 – 0.65 = 2.35
Hence mean number of children per family = 2.35

Question - 5 : -
The marks obtained out of 50, by 102 students in a Physics test are given in the frequency table below:
 
Find the average number of marks.

Answer - 5 : -


Question - 6 : - The number of students absent in a class were recorded every day for 120 days and the

Answer - 6 : -

Let assumed mean = 3
 
= 3 + 0.525 = 3.525 = 3.53 (approx)

Question - 7 : -
In the first proof reading of a book containing 300 pages the following distribution of misprints was obtained:
 
Find the average number of misprints per page.

Answer - 7 : -

Let assumed mean (A) = 2
 
= 2 – 127 = 0.73
∴ Average of number of misprints per page = 0.73

Question - 8 : -
The following distribution gives the number of accidents met by 160 workers in a factory during a month.
 
Find the average number of accidents per worker.

Answer - 8 : -

Let assumed mean = 2
 
= 2 – 1.168 = 2 – 1.17 = 0.83 (approx)
∴ Average number of accidents per worker = 0.83

Question - 9 : - Find the mean from the following frequency distribution of marks at a test in statistics

Answer - 9 : -

Let assumed mean = 25
 
∴Average of marked obtained per student = 22.075

Free - Previous Years Question Papers
Any questions? Ask us!
NodeJS Interview Questions Answers
ASP.Net Interview Questions Answers
Interview Questions Answers
×